CN113296132B - Remote sensor reflection band on-orbit angle response evaluation method based on pseudo-invariant target - Google Patents
Remote sensor reflection band on-orbit angle response evaluation method based on pseudo-invariant target Download PDFInfo
- Publication number
- CN113296132B CN113296132B CN202110550969.6A CN202110550969A CN113296132B CN 113296132 B CN113296132 B CN 113296132B CN 202110550969 A CN202110550969 A CN 202110550969A CN 113296132 B CN113296132 B CN 113296132B
- Authority
- CN
- China
- Prior art keywords
- pseudo
- data
- angle
- target
- reflectivity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/40—Correcting position, velocity or attitude
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- Geometry (AREA)
- General Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Image Processing (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
The invention discloses a remote sensor reflection band on-orbit angle response evaluation method based on a pseudo-invariant target, which comprises the following steps: screening a pseudo-unchanged target area; extracting pseudo-unchanged target data; constructing a pseudo-invariable target atmospheric roof direction model; correcting the atmospheric top direction characteristics of the pseudo-unchanged target; constructing an instrument radiation response angle dependence RVS; the invention is suitable for the technical field of satellite load calibration, and can obtain the angular dependence RVS of the instrument radiation response and the change characteristic of the RVS in-orbit time by carrying out pseudo-invariable target area screening, data extraction, model construction and direction characteristic correction, further obtain the normalized reflectivity time sequence after the correction of the atmospheric top direction characteristics of different pseudo-invariable targets, obtain the effective basis for satellite load calibration correction optimization based on the angular dependence of the obtained radiation response and improve the in-orbit calibration quality through data analysis.
Description
Technical Field
The invention belongs to the technical field of satellite load calibration, and particularly relates to a remote sensor reflection band on-orbit angle response evaluation method based on a pseudo-invariant target.
Background
The research of satellite remote sensors shows that the radiation response of solar reflection wave bands has a dependency relationship on the incident angle, in the process of remote sensor on-orbit radiation calibration treatment, the radiation response angle dependence RVS lookup table LUT is required to correct the radiation response difference under AOI of different incident angles, RVS is generally obtained by laboratory measurement before emission, and on-orbit RVS under specific angles can be obtained by utilizing a solar and diffuse reflection plate on-satellite calibration device and stable moon calibration observation.
RVS characteristics have changes in orbit, for example, the changes of the MODIS Terra and Aqua are respectively up to 35% and 20% under the influence of decay of the on-orbit response of the wave band 8, the satellite product precision is seriously influenced, and if a remote sensing instrument does not have a solar and diffuse reflection plate on-satellite calibration device and stable moon calibration observation, the angle dependence characteristic of the radiation response cannot be obtained in orbit according to the technical scheme.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides an on-orbit angle response evaluation method of a remote sensor reflection band based on a pseudo-invariant target.
In order to achieve the above purpose, the invention adopts the following technical scheme:
an on-orbit angle response evaluation method of a remote sensor reflection band based on a pseudo-invariant target comprises the following steps:
the method comprises the steps of screening a pseudo-unchanged target area, wherein the area screening principle is that the coverage area has a representative range, has good long-term stability and covers different scanning angles;
extracting pseudo-unchanged target data;
constructing a pseudo-invariable target atmospheric roof direction model;
correcting the atmospheric top direction characteristics of the pseudo-unchanged target;
constructing an instrument radiation response angle dependence RVS;
RVS on-orbit time variation characteristic analysis.
Preferably, the pseudo-unchanged target area includes, but is not limited to, the deserts Libya1, libya4, sonora, algeria5.
Preferably, the extracting of the pseudo invariable target data comprises the following steps:
acquiring effective clear sky data;
the scanning angle is divided into a plurality of angle intervals;
dividing the effective clear sky data into a plurality of effective clear sky data sets based on a plurality of angle intervals of the scanning angles, respectively correcting a cold sky background, a solar earth distance and a solar zenith angle of the plurality of effective clear sky data sets, and obtaining an atmospheric top reflectivity Ref time sequence of the effective clear sky data sets under the corresponding scanning angles based on a radiation calibration coefficient, wherein a calculation formula is as follows:
Ref＝Slope*(EV-SV)/(cos(solz)*dss)，
wherein, solz is solar zenith angle, dss is solar earth distance correction factor, SV is cold air background value, EV is earth observation digital value, slope is scaling factor.
Preferably, the acquiring effective clear sky data includes the following steps:
extracting earth observation data of a pseudo-invariant target central point N x N window, and screening near-sky bottom observation data;
taking the variation coefficient in the window as a clear sky criterion, detecting uniformity of window data, and forming a time sequence by window average data with the variation coefficient smaller than a threshold value TH;
setting a cloud detection reflectivity threshold MaxRef, and removing data with the band reflectivity larger than MaxRef;
calculating the mean value and standard deviation by M data points before and after each effective data in a sliding way to obtain a data mean value +/-1.5 standard deviation envelope curve, and removing data outside the envelope curve to obtain effective clear sky data;
the scanning angle grouping is divided into a plurality of angle intervals, and comprises the following steps: according to the statistical characteristics of the scanning angles of the instrument corresponding to the pseudo-invariant target, the scanning angles are grouped, and the possible ground scanning angle range is divided into a plurality of angle intervals.
Preferably, the value of N is 15, the threshold TH is 0.05, the M is 10, the MaxRef is 0.5, and the near nadir observations include, but are not limited to, satellite zenith angles SenZ <20 degrees.
Preferably, the constructing the pseudo-invariable target atmosphere top direction model includes:
for specific angle grouping data of a specific target, selecting a time period with a relatively stable calibration state, modeling by adopting a nuclear parameter BRDF model of MODIS based on atmospheric top reflectivity data and observation geometric data, and regressing to obtain a BRDF model parameter k 0 (lambda) and k 1 (λ)；
ρ(λ，θ,φ,ψ)＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)，
Wherein λ is the wavelength; θ, φ, and ψ are the solar zenith angle, satellite zenith angle, and relative azimuth, respectively; ρ is the atmospheric top reflectance, k 0 ，k 1 And k 2 For model coefficients, f 1 And f 2 Is bulk scattering and geometric optical nuclei.
Preferably, the correcting of the pseudo-invariant target atmospheric ceiling direction characteristic includes:
based on BRDF model parameters, performing directivity correction on the time sequence of the atmospheric top reflectivity data Ref to obtain a normalized reflectivity time sequence Ref after correction of the atmospheric top direction characteristics norm :
ρ 1 ＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)，
ρ 0 ＝k 0 (λ)+k 1 (λ)f 1 (0,0,0)+k 2 (λ)f 2 (0,0,0)，
Ref norm ＝Ref/ρ 1 *ρ 0 ，
Wherein ρ is 1 Atmospheric top reflectance, ρ, at instantaneous observation angles (θ, φ, ψ) calculated using the BRDF model 0 The atmospheric top reflectivity is when all three angles θ, φ, ψ are 0.
Preferably, the instrument radiation response angle dependence RVS construction includes:
setting a reference angle reference, and correcting normalized reflectivity time sequence Ref based on atmospheric top direction characteristics of different pseudo-unchanged targets norm Calculating the ratio of the normalized reflectivity to the normalized reflectivity of the reference angle to obtain RVS time sequence data corresponding to the incident angle AOI, and establishing a function relation between the RVS and the AOI in a quadratic polynomial form.
Preferably, the RVS on-orbit time varying characteristic analysis includes:
and drawing an RVS and time relation diagram according to the angle group based on the RVS time sequence.
In summary, due to the adoption of the technical scheme, the beneficial effects of the invention are as follows:
according to the invention, through screening a pseudo-invariable target area, extracting data, constructing a model, correcting direction characteristics, further obtaining normalized reflectivity time sequences of different pseudo-invariable targets after correcting the atmospheric top direction characteristics, obtaining an instrument radiation response angle dependence RVS and an RVS on-orbit time variation characteristic through data analysis, solving the problems of on-orbit evaluation monitoring and updating of the radiation response angle dependence characteristic, making up the defect of lacking a solar and diffuse reflection plate calibration device or stabilizing moon calibration observation, providing an effective basis for satellite load calibration correction optimization based on the obtained angle dependence of the radiation response, obtaining more stable radiation response, and improving on-orbit calibration quality.
Drawings
FIG. 1 is a flow chart of the present invention;
FIG. 2 is a flow chart of pseudo-invariant target clear sky data extraction in a preferred embodiment of the present invention;
FIG. 3 is a flow chart of pseudo-invariant target atmospheric ceiling-direction model construction in a preferred embodiment of the present invention;
FIG. 4 is a flow chart of a pseudo-invariant target atmospheric ceiling-direction characteristic correction in a preferred embodiment of the present invention;
FIG. 5 is a graph showing the time variation of the atmospheric top reflectivity Ref over different scan angle intervals in a preferred embodiment of the present invention;
FIG. 6 is a graph of normalized atmospheric top reflectance Ref for different scan angle intervals after correction of BRDF in a preferred embodiment of the invention norm Time-varying graph of (2);
figure 7 is a graph of RVS versus AOI in a preferred embodiment of the present invention;
figure 8 is a graph of RVS in-orbit time variation versus time in a preferred embodiment of the present invention.
Detailed Description
The following is a detailed description of an on-orbit angular response evaluation method of a remote sensor reflection band based on a pseudo-invariant target, with reference to fig. 1-8. The remote sensor reflection band on-orbit angle response evaluation method based on the pseudo-invariant target is not limited to the description of the following embodiments.
Example 1:
the embodiment provides a specific structure of a remote sensor reflection band on-orbit angle response evaluation method based on a pseudo-invariant target, as shown in fig. 1, comprising the following steps:
the method comprises the steps of screening a pseudo-unchanged target area, wherein the area screening principle is that the coverage area has a representative range, has good long-term stability and covers different scanning angles;
extracting pseudo-unchanged target data;
constructing a pseudo-invariable target atmospheric roof direction model;
correcting the atmospheric top direction characteristics of the pseudo-unchanged target;
constructing an instrument radiation response angle dependence RVS;
RVS on-orbit time variation characteristic analysis.
Specifically, the pseudo-unchanged target area includes, but is not limited to, the deserts Libya1, libya4, sonora, algeria.
Specifically, the pseudo-invariant target data extraction includes the steps of:
acquiring effective clear sky data;
the scanning angle is divided into a plurality of angle intervals;
dividing the effective clear sky data into a plurality of effective clear sky data sets based on a plurality of angle intervals of the scanning angles, respectively correcting a cold sky background, a solar earth distance and a solar zenith angle of the plurality of effective clear sky data sets, and obtaining an atmospheric top reflectivity data Ref time sequence of the effective clear sky data sets under the corresponding scanning angles based on a radiation calibration coefficient, wherein a calculation formula is as follows:
Ref＝Slope*(EV-SV)/(cos(solz)*dss)，
wherein, solz is solar zenith angle, dss is solar earth distance correction factor, SV is cold air background value, EV is earth observation digital value, slope is scaling factor.
Specifically, obtaining effective clear sky data includes the following steps:
extracting earth observation data of a pseudo-invariant target central point N x N window, and screening near-sky bottom observation data;
taking the variation coefficient in the window as a clear sky criterion, detecting uniformity of window data, and forming a time sequence by window average data with the variation coefficient smaller than a threshold value TH;
setting a cloud detection reflectivity threshold MaxRef, and removing data with the band reflectivity larger than MaxRef;
calculating the mean value and standard deviation by M data points before and after each effective data in a sliding way to obtain a data mean value +/-1.5 standard deviation envelope curve, and removing data outside the envelope curve to obtain effective clear sky data;
the scanning angle grouping is divided into a plurality of angle intervals, and comprises the following steps: according to the statistical characteristics of the scanning angles of the instrument corresponding to the pseudo-invariant target, the scanning angles are grouped, and the possible ground scanning angle range is divided into a plurality of angle intervals.
Specifically, the value of N is 15, the threshold TH is 0.05, m is 10, maxref is 0.5, and near nadir observations include, but are not limited to, satellite zenith angles SenZ <20 degrees.
Further, the constructing of the pseudo-invariable target atmosphere top direction model comprises the following steps:
for specific angle grouping data of a specific target, selecting a time period with a relatively stable calibration state, modeling by adopting a nuclear parameter BRDF model of MODIS based on atmospheric top reflectivity data and observation geometric data, and regressing to obtain a BRDF model parameter k 0 (lambda) and k 1 (λ)；
ρ(λ，θ,φ,ψ)＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)，
Wherein λ is the wavelength; θ, φ, and ψ are the solar zenith angle, satellite zenith angle, and relative azimuth, respectively; ρ is the atmospheric top reflectance, k 0 ，k 1 And k 2 For model coefficients, f 1 And f 2 Is bulk scattering and geometric optical nuclei.
Further, the correcting of the pseudo-invariant target atmospheric ceiling direction characteristic includes:
based on BRDF model parameters, performing directivity correction on the time sequence of the atmospheric top reflectivity data Ref to obtain a normalized reflectivity time sequence Ref after correction of the atmospheric top direction characteristics norm ；
ρ 1 ＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)，
ρ 0 ＝k 0 (λ)+k 1 (λ)f 1 (0,0,0)+k 2 (λ)f 2 (0,0,0)，
Ref norm ＝Ref/ρ 1 *ρ 0 ，
Wherein ρ is 1 Atmospheric top reflectance, ρ, at instantaneous observation angles (θ, φ, ψ) calculated using the BRDF model 0 The atmospheric top reflectivity is when all three angles θ, φ, ψ are 0.
Further, the construction of the instrument radiation response angle dependence RVS comprises the following steps:
setting a reference angle reference, and correcting normalized reflectivity time sequence Ref based on atmospheric top direction characteristics of different pseudo-unchanged targets norm Calculating the ratio of the normalized reflectivity of each angle group to the normalized reflectivity of the reference angle to obtain an RVS time sequence corresponding to the incident angle AOI, and establishing a function relation between the RVS and the AOI:
RVS＝1.01020414e+1.36841819e-03*AOI-2.56414528e-05*(AOI,)- 2 。
further, the RVS on-orbit time varying characteristic analysis includes:
and drawing an RVS and time relation diagram according to the angle group based on the RVS time sequence.
Example 2:
the embodiment provides a specific structure of a remote sensor reflection band on-orbit angle response evaluation method based on a pseudo-invariable target, as shown in fig. 2-8, the observation data of a band 1 desert stable target of FY-3B VIRR is taken as an example, the influence of the observation angle on the reflection band observation reflectivity of a VIRR instrument is analyzed and judged, a BRDF model is established, the influence of the observation angle on the observation reflectivity is removed by the BRDF model, and then the dependency relationship between the instrument radiation response and the satellite observation angle is obtained. The invention will be further described with reference to the accompanying drawings and specific examples.
S1, screening a pseudo-invariant target region:
based on a pseudo-invariant target screening principle: the coverage area has a representative range, good long-term stability of the area, needs to cover different scanning angles, integrates various factors, and finally selects deserts Libya1, libya4 and Sonora, algeria5 as pseudo-invariant data extraction sites.
S2, extracting clear sky data of the pseudo-invariant target:
as shown in fig. 2, the specific implementation steps are as follows:
firstly, extracting pseudo-unchanged target data, and carrying out clear sky screening.
Taking the longitude and latitude of the pseudo-invariant target as a center, extracting 15×15 window earth observation data, and screening near-sky bottom observation data (satellite zenith angle is smaller than 20 °);
based on earth observation data EV, performing cold air background, solar earth distance and solar zenith angle correction, and based on a scaling coefficient Slope, calculating the atmospheric Top (TOA) reflectivity Ref of each pixel in the window:
Ref＝Slope*(EV-SV)/(cos(solz)*dss)，
wherein SV is the cold air background value, solz is the solar zenith angle, and dss is the distance between the sun and the earth.
Calculating a window variation coefficient: CV = STD/AVE, where STD and AVE are standard deviation and mean of 15 x 15 window reflectivities, respectively;
and screening window data to form a time sequence. Screening conditions: CV <0.05, band 1TOA average reflectivity <0.5;
for each effective data in the time sequence, 20 points of the front 10 points and the rear 10 points are taken as sliding windows, the average value AVE and standard deviation STD of the reflectivity in the sliding windows are calculated, and data except envelope curves AVE+1.5 STD and AVE-1.5 STD are removed to serve as target effective clear sky data.
And secondly, grouping the scanning angles according to the statistical characteristics of the instrument scanning angles corresponding to the pseudo-invariant targets. Specifically, the scanning angle is converted into 0-110 degrees from-55 to +55 degrees, and the scanning angles are equally divided into four angles of 9-32 degrees, 32-55 degrees, 55-78 degrees and 78-101 degrees after the scanning ends are removed. The corresponding scan angle is calculated based on the observed column number of the valid data. The observation column number Col is converted into an earth observation angle value AOI.
And grouping the effective clear sky data according to the remote sensor scanning angles to obtain an atmospheric top reflectivity data Ref time sequence of the specific target under each group of scanning angles.
As shown in fig. 5, time-series data Ref of atmospheric top reflectivity for different scan angle intervals are obtained.
S3, constructing a pseudo-invariant target atmosphere top direction model:
as shown in fig. 3, the specific implementation steps are as follows:
and 2, selecting data stabilization period data of 2010, 2011 and 2012 for 3 years continuously by using the time series data of the atmospheric top reflectivity of different scanning angle intervals obtained in the step 2, and carrying out directional characteristic modeling based on the following formula:
ρ＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)，
wherein λ is the wavelength; θ, φ, and ψ are the solar zenith angle, satellite zenith angle, and relative azimuth, respectively; ρ is the atmospheric top reflectivity; f (f) 1 And f 2 Is an angle dependent bulk scattering and geometrical optics kernel; k (k) 0 ，k 1 And k 2 The resulting model coefficients are fitted.
S4, correcting the pseudo-invariant target atmosphere top direction characteristics:
as shown in fig. 4, the specific implementation steps are as follows:
and (3) respectively calculating the atmospheric top reflectivity model estimated values under 2 observation geometries by using the model coefficients obtained in the step (3):
ρ(λ,θ,φ,ψ)＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)，
ρ 0 (λ,0,0,0)＝k 0 (λ)+k 1 (λ)f 1 (0,0,0)+k 2 (λ)f 2 (0,0,0)，
obtaining a normalized reflectivity time sequence Ref after direction characteristic correction norm ：
Ref norm ＝Ref/ρ*ρ 0 。
As shown in FIG. 6, a normalized reflectance time series Ref after correction of the atmospheric ceiling direction characteristics in different scan angle intervals is obtained norm 。
S5, constructing a radiation response angle dependence relation of the instrument:
the specific implementation steps are as follows:
normalized reflectivity time sequence Ref obtained after correction of atmospheric top direction characteristics of different pseudo-unchanged targets in step 4 norm Selecting data in the data stabilization periods of 2010, 2011 and 2012;
using 60 degrees as an incident Angle (AOI) reference angle, fitting by using data of a third angle interval for each year to obtain a relation (quadratic polynomial) between the incident angle and the normalized reflectivity, and estimating the normalized reflectivity when the incident angle of the corresponding year is 60 degrees according to the relation;
calculating the ratio of the normalized reflectivity at other incidence angles to the normalized reflectivity at the incidence angle of 60 degrees in the corresponding year for each year to obtain the year RVS and AOI data sequence as the RVS of the incidence angle; as shown in fig. 7, the relationship between RVSs and incident angles AOI for different years is obtained, and the relationship modeling can be performed by using a polynomial.
S6 RVS on-orbit time variation characteristic analysis:
the specific implementation steps are as follows:
utilizing the RVS and AOI data sequences obtained in the step 4;
as shown in fig. 8, RVS versus time is plotted over a particular angular range.
RVSs exhibit a long-term steady-state trend of data over time over a particular angular set.
Working principle: as shown in figures 1-8, the method comprises the steps of screening a pseudo-unchanged target area, extracting data, constructing a model, correcting direction characteristics, further obtaining normalized reflectivity time sequences of different pseudo-unchanged targets after correcting the atmospheric top direction characteristics, analyzing the data, obtaining an instrument radiation response angle dependence RVS and RVS on-orbit time variation characteristics, solving the problems of on-orbit evaluation monitoring and updating of the radiation response angle dependence characteristics, making up for the defect of lack of a solar and diffuse reflection plate calibration device or stable moon calibration observation, providing effective basis for satellite load calibration correction optimization based on the obtained angle dependence of the radiation response, obtaining more stable radiation response, and improving on-orbit calibration quality.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.
Claims (9)
1. The remote sensor reflection band on-orbit angle response evaluation method based on the pseudo-invariant target is characterized by comprising the following steps of:
the method comprises the steps of screening a pseudo-unchanged target area, wherein the area screening principle is that the coverage area has a representative range, has good long-term stability and covers different scanning angles;
extracting pseudo-unchanged target data;
constructing a pseudo-invariable target atmospheric roof direction model;
correcting the atmospheric top direction characteristics of the pseudo-unchanged target;
constructing an instrument radiation response angle dependence RVS;
RVS on-orbit time variation characteristic analysis;
s1, screening a pseudo-invariant target region:
selecting desert Libya1, libya4 and Sonora, algeria as pseudo-invariant data extraction sites;
s2, extracting pseudo-unchanged target data:
firstly, extracting the clear sky data of a pseudo unchanged target, wherein the specific implementation steps are as follows:
extracting earth observation data of a pseudo-unchanged target, and detecting clear sky with a 15 x 15 window;
calculating standard deviation and average value of target reflectivity of all wave bands of a 15 x 15 window; calculating the variation coefficient of each wave band: CV = STD/AVE; wherein STD is standard deviation of target reflectivity; AVE is the mean value of the target reflectivity;
data screening is carried out on all wave bands, and screening conditions are as follows: CV <0.05 for each band, band 1 atmospheric top average reflectivity <0.5; the zenith angle of the satellite is smaller than 20 degrees; outputting a cloud rejection time sequence;
based on the cloud rejection time sequence, 20 points of the front 10 points and the rear 10 points are taken as sliding windows to calculate the average value AVE and standard deviation STD of the reflectivity of the 4 th wave band, and the upper envelope and the lower envelope are output: ave+1.5 std, AVE-1.5 std; filtering abnormal data outside the envelope; outputting effective clear sky data;
secondly, grouping the scanning angles according to the statistical characteristics of instrument scanning angles corresponding to the pseudo-invariant targets, converting the scanning angles from-55 degrees to +55 degrees into 0-110 degrees, and dividing the scanning angles into four angles ranging from 9-32 degrees, 32-55 degrees, 55-78 degrees and 78-101 degrees;
thirdly, grouping effective clear sky data according to a remote sensor scanning angle, correcting a cool sky background, a solar earth distance and a solar zenith angle of each group, and obtaining an atmospheric top reflectivity data Ref time sequence of a specific target under a corresponding scanning angle based on a radiation calibration coefficient;
the method comprises the following specific steps:
reading EV values, solar zenith angles, SV values and observation Column numbers in the effective clear sky data;
converting the observed Column number Columbn value into a ground observation angle value Pixangle (0-110 degrees);
pixangle is stripped of both ends and equally divided into 4 angular ranges:
9-32 degrees, 32-55 degrees, 55-78 degrees, 78-101 degrees;
the atmospheric top reflectivity is calculated, and the calculation formula is as follows:
Ref＝Slope*(EV-SV)/(cos(solz)*dss)；
wherein Ref is the atmospheric top reflectivity; EV is an earth observation digital value; SV is the cold air background value; slope is the radiometric scaling factor; the solz is the zenith angle of the sun; dss is a daily distance correction factor;
acquiring time series data of the atmospheric top reflectivity under different angles and different targets;
s3, constructing a pseudo-invariant target atmosphere top direction model:
the specific implementation steps are as follows:
reading EV value, solar zenith angle, SV value, observation Column number Column value, star time and day count DSL and target scaling coefficient in the effective clear sky data;
converting the observed Column number Columbn value into a ground observation angle value Pixangle (0-110 degrees);
pixangle is stripped of both ends and equally divided into 4 angular ranges: 9-32 degrees, 32-55 degrees, 55-78 degrees, 78-101 degrees;
calculating a target scaling coefficient: ref_fslope=k0+k1+k2+k2 DSL, where k0, k1, k2 are parameters of the scaling model; DSL is the time of staring, and day is the counting unit;
calculating the target reflectivity: after EV subtracts cold air SV and multiplies the target calibration coefficient ref_fslope, solar zenith angle and solar earth distance correction are carried out, and target reflectivity is obtained, wherein the calculation formula of the target reflectivity is as follows:
ref_f＝ref_fslope*(EV-SV)/(cos(solz)*dss)；
inputting solar zenith angle, satellite zenith angle, relative azimuth angle and target reflectivity data for modeling, and fitting to obtain model parameters k 0 (λ)、k 1 (lambda) and k 2 (λ)；
ρ(λ，θ,φ,ψ)＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)；
Wherein λ is the wavelength; ρ is the calculated atmospheric top reflectivity, k of the model 0 ，k 1 And k 2 For model coefficients, f 1 And f 2 Is a model of the volume scattering and geometric optical kernel function; θ is the solar zenith angle; phi is the zenith angle of the satellite; psi is the relative azimuth;
s4, correcting the pseudo-invariant target atmosphere top direction characteristics:
the specific implementation steps are as follows:
using the model parameters k obtained in step S3 0 、k 1 And k 2 Performing directivity correction on the atmospheric top reflectivity data to obtain normalized reflectivity after correction of atmospheric top direction characteristics:
ref1＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)，
ref0＝k 0 (λ)+k 1 (λ)f 1 (0,0,0)+k 2 (λ)f 2 (0,0,0)，
ref_norm＝ref_f/ref1*ref0，
wherein, ref1 is the atmospheric top reflectivity under the instantaneous observation angles (theta, phi) calculated by adopting the model, and ref0 is the atmospheric top reflectivity calculated by adopting the model when the three angles of theta, phi and phi are all 0; ref_f is the atmospheric top reflectivity data; ref_norm is the normalized reflectivity;
s5, constructing a radiation response angle dependence relation of the instrument:
the specific implementation steps are as follows:
reading the normalized reflectivity time sequence obtained in the step S4 after the atmospheric top direction characteristics of different pseudo-unchanged targets are corrected;
dividing the normalized reflectivity into 4 angle groups, and respectively selecting stable period data of 3 consecutive years;
taking a scanning angle as a reference angle, calculating the ratio of the normalized reflectivity of other remote sensors to the normalized reflectivity of the reference angle, and taking the ratio as RVS of the scanning angle;
establishing a function relation between RVS and AOI by using polynomial fitting; wherein RVS is the dependence of instrument radiation response angle; AOI is the scan angle;
s6 RVS on-orbit time variation characteristic analysis
The specific implementation steps are as follows:
and (5) reading RVS results of different years obtained in the step (S5), and drawing a RVS and time relation diagram according to the angle group.
2. The method for evaluating the on-orbit angular response of the reflection band of the remote sensor based on the pseudo-invariant target as claimed in claim 1, wherein the method comprises the following steps: the pseudo-invariant target regions include, but are not limited to, the deserts Libya1, libya4, sonora, algeria.
3. The method for evaluating the on-orbit angular response of the reflection band of the remote sensor based on the pseudo-invariant target as claimed in claim 2, wherein the pseudo-invariant target data extraction comprises the following steps:
acquiring effective clear sky data;
the scanning angle is divided into a plurality of angle intervals;
dividing the effective clear sky data into a plurality of effective clear sky data sets based on a plurality of angle intervals of the scanning angles, respectively correcting a cold sky background, a solar earth distance and a solar zenith angle of the plurality of effective clear sky data sets, and obtaining an atmospheric top reflectivity data Ref time sequence of the effective clear sky data sets under the corresponding scanning angles based on the radiometric calibration coefficients.
4. The method for evaluating the on-orbit angular response of the reflection band of the remote sensor based on the pseudo-invariant target as claimed in claim 3, wherein the step of obtaining effective clear sky data comprises the following steps:
extracting earth observation data of a pseudo-invariant target central point N x N window, and screening near-sky bottom observation data;
taking the variation coefficient in the window as a clear sky criterion, detecting uniformity of window data, and forming a time sequence by window average data with the variation coefficient smaller than a threshold value TH;
setting a cloud detection reflectivity threshold MaxRef, and removing data with the band reflectivity larger than MaxRef;
calculating the mean value and standard deviation by M data points before and after each effective data in a sliding way to obtain a data mean value +/-1.5 standard deviation envelope curve, and removing data outside the envelope curve to obtain effective clear sky data;
the scanning angle grouping is divided into a plurality of angle intervals, and comprises the following steps: according to the statistical characteristics of the scanning angles of the instrument corresponding to the pseudo-invariant target, the scanning angles are grouped, and the possible ground scanning angle range is divided into a plurality of angle intervals.
5. The method for evaluating the on-orbit angular response of the reflection band of the remote sensor based on the pseudo-invariant target as claimed in claim 4, wherein the method comprises the following steps: the value of N is 15, the threshold TH is 0.05, M is 10, maxRef is 0.5, and the near-nadir observations include, but are not limited to, satellite zenith angles SenZ.
6. The method for evaluating the on-orbit angular response of a remote sensor reflection band based on a pseudo-invariant target according to claim 5, wherein the pseudo-invariant target atmospheric ceiling direction model construction comprises:
for specific angle grouping data of a specific target, selecting a time period with a relatively stable calibration state, modeling based on the atmospheric top reflectivity data and the observation geometric data, and regressing to obtain a model parameter k 0 (λ)、k 1 (lambda) and k 2 (λ)；
ρ - (λ,θ,φ,ψ)＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)，
Wherein λ is the wavelength; θ, φ, and ψ are the solar zenith angle, satellite zenith angle, and relative azimuth, respectively; ρ - Atmospheric top reflectance, k, calculated for the model 0 ，k 1 And k 2 For model coefficients, f 1 And f 2 Is a model of volume scattering and geometric optical kernel function.
7. The method for evaluating the on-orbit angular response of a reflection band of a remote sensor based on a pseudo-invariant target according to claim 6, wherein the correcting of the atmospheric top direction characteristic of the pseudo-invariant target comprises:
based on model parameters, performing directivity correction on the time sequence of the atmospheric top reflectivity data Ref to obtain a normalized reflectivity time sequence Ref with corrected atmospheric top direction characteristics - norm ；
ρ - (λ,θ,φ,ψ)＝k 0 (λ)+k 1 (λ)f 1 (θ,φ,ψ)+k 2 (λ)f 2 (θ,φ,ψ)，
ρ - 0 (λ,0,0,0)＝k 0 (λ)+k 1 (λ)f 1 (0,0,0)+k 2 (λ)f 2 (0,0,0)，
Ref - norm ＝Ref/ρ - *ρ - 0 ；
Wherein ρ is - For calculating instantaneous observation angles using modelsAtmospheric top reflectance at degrees (θ, φ, ψ), ρ - 0 For the model calculated atmospheric top reflectivity, ref, when all three angles of theta, phi and phi are 0 - norm In order to actually observe the normalized reflectivity of the atmospheric top reflectivity Ref (theta, phi) after the correction of the direction characteristics when the three angles of theta, phi and phi are all 0.
8. The method for evaluating the on-orbit angular response of the reflection band of the remote sensor based on the pseudo-invariant target of claim 7, wherein the instrument radiation response angular dependency construction comprises the following steps:
setting a reference angle reference, and correcting normalized reflectivity time sequence Ref based on atmospheric top direction characteristics of different pseudo-unchanged targets norm Calculating the ratio of the normalized reflectivity time of each angle group to the normalized reflectivity time of the reference angle, taking the ratio as the RVS corresponding to the angle group scanning angle AOI, and establishing a function relation between the RVS and the AOI by adopting polynomial fitting.
9. The method for evaluating the on-orbit angular response of the reflection band of the remote sensor based on the pseudo-invariant target as claimed in claim 8, wherein the analysis of the on-orbit time variation characteristics of the RVS comprises the following steps:
based on the normalized reflectivity ref_norm time sequence corrected by the atmospheric top direction characteristics of different pseudo-invariable targets, dividing the normalized reflectivity into 4 angle groups, respectively selecting stable period data of 3 continuous years, and drawing an RVS and time relation diagram.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110550969.6A CN113296132B (en) | 2021-05-20 | 2021-05-20 | Remote sensor reflection band on-orbit angle response evaluation method based on pseudo-invariant target |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110550969.6A CN113296132B (en) | 2021-05-20 | 2021-05-20 | Remote sensor reflection band on-orbit angle response evaluation method based on pseudo-invariant target |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113296132A CN113296132A (en) | 2021-08-24 |
| CN113296132B true CN113296132B (en) | 2023-07-25 |
Family
ID=77323090
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110550969.6A Active CN113296132B (en) | 2021-05-20 | 2021-05-20 | Remote sensor reflection band on-orbit angle response evaluation method based on pseudo-invariant target |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113296132B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114200549B (en) * | 2021-12-10 | 2022-07-01 | 北京华云星地通科技有限公司 | Remote sensing instrument radiation stability detection method and system based on stable target |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565778B (en) * | 2011-12-12 | 2014-09-24 | 中国科学院遥感与数字地球研究所 | Relative radiometric correction method for automatically extracting pseudo-invariant features for remote sensing image |
| CN105092055B (en) * | 2015-08-21 | 2018-01-16 | 国家卫星气象中心 | Meteorological satellite sun reflected waveband Calibration Method based on cold cloud target |
| ITUB20160628A1 (en) * | 2016-02-10 | 2017-08-10 | St Microelectronics Srl | PROCEDURE FOR PREDICTING THE ORBIT OF A SATELLITE AND CORRESPONDING SATELLITE SIGNAL RECEIVER |
-
2021
- 2021-05-20 CN CN202110550969.6A patent/CN113296132B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN113296132A (en) | 2021-08-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Lyapustin et al. | Scientific impact of MODIS C5 calibration degradation and C6+ improvements | |
| Remsberg et al. | The validation of Nimbus 7 LIMS measurements of ozone | |
| Collard et al. | The assimilation of infrared atmospheric sounding interferometer radiances at ECMWF | |
| CN110987821B (en) | Hyperspectral rapid atmospheric correction parameterization method | |
| CN112798013B (en) | Method for verifying on-orbit absolute radiometric calibration result of optical load | |
| CN113296132B (en) | Remote sensor reflection band on-orbit angle response evaluation method based on pseudo-invariant target | |
| Wu et al. | Carbon dioxide retrieval from OCO-2 satellite observations using the RemoTeC algorithm and validation with TCCON measurements | |
| CN110836870B (en) | GEE-based large-area lake transparency rapid drawing method | |
| CN110109149B (en) | Laser radar low-layer extinction coefficient profile correction method | |
| CN112505651B (en) | Automatic processing method for atmospheric detection laser radar | |
| CN111859695A (en) | Atmospheric pollution component inversion method based on high-resolution five-satellite ultraviolet visible hyperspectrum | |
| CN115265783B (en) | Multi-platform understar instantaneous cross calibration method based on hyperspectral data | |
| CN113532652A (en) | Infrared remote sensing sensor absolute calibration method based on buoy and atmospheric reanalysis data | |
| CN112924391A (en) | FY-4A/AGRI cross radiation calibration method based on remote sensing big data | |
| de Lange et al. | Methane profiles from GOSAT thermal infrared spectra | |
| Green et al. | In-flight validation and calibration of the spectral and radiometric characteristics of the airborne visible/infrared imaging spectrometer | |
| CN115792973A (en) | Moon-based satellite optical remote sensor radiation calibration method | |
| CN113607654B (en) | Global glyoxal concentration remote sensing inversion method and system based on hyperspectral satellite | |
| Cobos et al. | Assessment of the impact of meteorological conditions on pyrheliometer calibration | |
| CN114674461A (en) | Method and device for determining sea surface temperature and readable storage medium | |
| Chang et al. | Development of a near-sea-level calibration algorithm for aerosol optical depth measurement using a ground-based spectrometer | |
| KR20100028337A (en) | Method for calibration of coms throught cloud using cloud target | |
| CN110411565B (en) | Method for deducing high-spectrum earth surface reflectivity from multi-spectrum earth surface reflectivity | |
| Schrijver et al. | Water vapour total columns from SCIAMACHY spectra in the 2.36 μm window | |
| Faizoun et al. | Monitoring of Sahelian aerosol and atmospheric water vapor content characteristics from sun photometer measurements |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |